title: Correlation of minimum apparent diffusion coefficient with maximum standardized uptake on fluorodeoxyglucose PET-CT in patients with rectal adenocarcinoma.
abstract: OBJECTIVE
  The aim of this study was to retrospectively assess the correlation between minimum apparent diffusion coefficient (ADCmin) values obtained from diffusion-weighted magnetic resonance imaging (MRI) and maximum standardized uptake values (SUVmax) obtained from positron emission tomography-computed tomography (PET-CT) in rectal cancer.
  
  
  METHODS
  Forty-one patients with pathologically confirmed rectal adenocarcinoma were included in this study. For preoperative staging, PET-CT and pelvic MRI with diffusion-weighted imaging were performed within one week (mean time interval, 3±1 day). For ADC measurements, the region of interest (ROI) was manually drawn along the border of each hyperintense tumor on b=1000 s/mm2 images. After repeating this procedure on each consecutive tumor-containing slice to cover the entire tumoral area, ROIs were copied to ADC maps. ADCmin was determined as the lowest ADC value among all ROIs in each tumor. For SUVmax measurements, whole-body images were assessed visually on transaxial, sagittal, and coronal images. ROIs were determined from the lesions observed on each slice, and SUVmax values were calculated automatically. The mean values of ADCmin and SUVmax were compared using Spearman's test.
  
  
  RESULTS
  The mean ADCmin was 0.62±0.19×10-3 mm2/s (range, 0.368-1.227×10-3 mm2/s), the mean SUVmax was 20.07±9.3 (range, 4.3-49.5). A significant negative correlation was found between ADCmin and SUVmax (r=-0.347; P = 0.026).
  
  
  CONCLUSIONS
  There was a significant negative correlation between the ADCmin and SUVmax values in rectal adenocarcinomas.
authors.affiliation: From the Departments of Radiology (H.Ç.E., A.E. e-mail: ayse.erden@medicine.ankara.edu.tr), Nuclear Medicine (N.Ö.K.), and General Surgery (E.G.), Ankara University School of Medicine, Ankara, Turkey.
authors.forename: Hale Çolakoğlu
authors.initials: HÇ
authors.lastname: Er
authors.forename: Ayşe
authors.initials: A
authors.lastname: Erden
authors.forename: N Özlem
authors.initials: NÖ
authors.lastname: Küçük
authors.forename: Ethem
authors.initials: E
authors.lastname: Geçim
mesh_terms: D000230:Adenocarcinoma / Q000175:diagnosis*; D000328:Adult; D000368:Aged; D005260:Female; D019788:Fluorodeoxyglucose F18 / Q000493:pharmacokinetics; D006801:Humans; D008297:Male; D008875:Middle Aged; D064847:Multimodal Imaging; D049268:Positron-Emission Tomography; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics; D012004:Rectal Neoplasms / Q000175:diagnosis*; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18